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[Test] Add test showing that we can avoid inserting trunc/zext

This commit is contained in:
Max Kazantsev 2020-10-07 12:18:24 +07:00
parent 5a3f6bfe8a
commit 0c009e092e
1 changed files with 52 additions and 0 deletions
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52
llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll
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@ -544,3 +544,55 @@ define i32 @test10(i32 %v) {
leave:
ret i32 22
}
; TODO: We don't really need trunc/zext here because when iv.next overflows,
; its value is not used.
define i32 @test11(i32 %start, i32* %p, i32* %q) {
; CHECK-LABEL: @test11(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = zext i32 [[START:%.*]] to i64
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[BACKEDGE:%.*]] ], [ [[TMP0]], [[ENTRY:%.*]] ]
; CHECK-NEXT: [[TMP1:%.*]] = trunc i64 [[INDVARS_IV]] to i32
; CHECK-NEXT: [[IV_NEXT:%.*]] = add i32 [[TMP1]], -1
; CHECK-NEXT: [[COND:%.*]] = icmp eq i64 [[INDVARS_IV]], 0
; CHECK-NEXT: br i1 [[COND]], label [[EXIT:%.*]], label [[BACKEDGE]]
; CHECK: backedge:
; CHECK-NEXT: [[INDEX:%.*]] = zext i32 [[IV_NEXT]] to i64
; CHECK-NEXT: [[STORE_ADDR:%.*]] = getelementptr i32, i32* [[P:%.*]], i64 [[INDEX]]
; CHECK-NEXT: store i32 1, i32* [[STORE_ADDR]], align 4
; CHECK-NEXT: [[LOAD_ADDR:%.*]] = getelementptr i32, i32* [[Q:%.*]], i64 [[INDEX]]
; CHECK-NEXT: [[STOP:%.*]] = load i32, i32* [[Q]], align 4
; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp eq i32 [[STOP]], 0
; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1
; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[FAILURE:%.*]]
; CHECK: exit:
; CHECK-NEXT: ret i32 0
; CHECK: failure:
; CHECK-NEXT: unreachable
;
entry:
br label %loop
loop:
%iv = phi i32 [%start, %entry], [%iv.next, %backedge]
%iv.next = add i32 %iv, -1
%cond = icmp eq i32 %iv, 0
br i1 %cond, label %exit, label %backedge
backedge:
%index = zext i32 %iv.next to i64
%store.addr = getelementptr i32, i32* %p, i64 %index
store i32 1, i32* %store.addr
%load.addr = getelementptr i32, i32* %q, i64 %index
%stop = load i32, i32* %q
%loop.cond = icmp eq i32 %stop, 0
br i1 %loop.cond, label %loop, label %failure
exit:
ret i32 0
failure:
unreachable
}